Introduction to Memory Management in Linux

The Linux kernel orchestrates system memory with precision, allocating resources for processes efficiently. It manages memory through paging, swapping, and virtual memory techniques, ensuring optimal performance and multitasking capabilities.

Linux uses Slab allocators like SLUB, SLOB, and SLAB to manage kernel objects. They optimize memory usage by caching commonly used objects, minimizing fragmentation and speeding up allocation and deallocation.

Virtual memory abstracts physical RAM, allowing processes to use more memory than physically available. The kernel's page table maps virtual addresses to physical counterparts, facilitating process isolation and memory overcommitment handling.

Linux employs demand paging to load pages into memory only when accessed. This lazy loading approach conserves memory, reduces I/O, and can handle larger applications than the available physical memory.

Transparent HugePages enhance performance by allowing the kernel to use larger memory pages, reducing page table entries and TLB misses. This is especially beneficial for large dataset operations.

KSM is a memory-saving de-duplication feature. By scanning pages and merging identical ones, KSM frees up RAM, enabling higher density in virtualized environments without additional hardware.

The kernel exposes APIs like kmalloc and vmalloc for memory allocation. While kmalloc is quick and used for small, contiguous memory, vmalloc suits larger, non-contiguous allocations by mapping them into a contiguous virtual space.